1. Field of the Invention
The present invention is aimed at cleansing a variety of bacteria and contaminants and relates to an electrode for electrolysis which is capable of producing ozone and active oxygen with high efficiency, a production process of the electrode, an electrolytic process using the electrode, and an electrolyzed water producing device using the electrode.
2. Description of the Related Art
Heretofore, to remove microorganisms such as bacteria, fungi and protozoans contained in domestic water for drinking and cooking and water (hereinafter referred to as “for-treatment water”) used in a kitchen or other places, a method in which the for-treatment water is sterilized and purified by use of a chlorine-based agent such as sodium hypochlorite has been used. However, the for-treatment water contains chlorine-resistant bacteria, spores and protozoans, and they are difficult to remove by use of only hypochlorous acid. Hence, a method in which the for-treatment water is sterilized and purified by use of ozone is used.
As means for producing the ozone, it is generally practiced to use, as an anode, an electrode for electrolysis which comprises a titanium substrate whose surface is coated with a lead oxide or a tin oxide. The electrode coated with the lead oxide or tin oxide is capable of producing ozone and active oxygen with high efficiency. Therefore, the electrode can be considered particularly effective when the fore-treatment water is treated with high concentrations of ozone and active oxygen.
However, since the lead oxide is designated as a toxic substance by water quality regulations as a lead compound, the electrode coated with the lead oxide has a problem that when water treated with the electrode is taken in a human body, the water causes a variety of troubles in the human body. Meanwhile, the electrode coated with the tin oxide has a problem in terms of durability since the tin oxide is liable to be eluted by electrolysis. Thus, there has been a problem that it is difficult to carry out electrolysis of for-treatment water by use of an electrode for electrolysis which has a substrate coated with the lead oxide or tin oxide.
Under the circumstances, to avoid the above problems, a method has been used in which ozone is produced by use of an electrode for electrolysis which has a substrate coated with a noble metal such as platinum or a metal oxide. However, the method has a problem that with the electrode, the efficiency of production of ozone is significantly lower than that with an electrode coated with a lead oxide.
Accordingly, the amount of ozone dissolved in for-treatment water is small, so that the sterilizing effect of ozone is not so favorable.
Meanwhile, a problem of infectious diseases caused by bacteria such as Legionella bacteria which grow in a bathroom in particular has recently been receiving attention. At humidities and temperatures in a bathroom, growth of fungi and proliferation of bacteria such as Legionella bacteria are spurred, and when these fungi and Legionella bacteria enter a human body, they cause infectious diseases in the human body. In general, fungi and Legionella bacteria which have proliferated in an environment with high humidity and temperature such as a bathroom are deposited on a bathtub and tiles and diffused into hot water reserved in the bathtub. When one inhales steam generated from the hot water, the bacteria enter his body.
Further, in addition to the bathtub, in sinks as in a kitchen, when small pieces of food or water are rotten, they cause proliferation of bacteria.
In addition, the foregoing bacteria such as Legionella bacteria are also stuck to an air conditioner, air cleaner, ventilating fan, and the like, and upon operation of these apparatuses, the bacteria are discharged into a room from an air outlet and float in the air. There is a problem that these floating bacteria cause infectious diseases.
Under the circumstances, a chlorine-based bactericide is generally applied to a bathtub, tiles, kitchen sink and air outlet as of air conditioning equipment where bacteria such as fungi and Legionella bacteria are deposited, so as not only to kill the bacteria such as fungi but also to prevent further proliferation of the bacteria.
Most of generally used chlorine-based bactericides are adjusted to be alkaline by incorporation of agents such as sodium hypochlorite. Further, the chlorine-based bactericide has a problem that it generates a chlorine gas when mixed with an acidic agent, thereby causing an accident during use. In addition, the chlorine-based bactericide also has a problem that it has difficulty in eliminating chlorine-resistant bacteria, spores and protozoans.
Further, as another sterilization method, a sterilization method using silver ions as bactericidal metal ions is known. The sterilization method based on the silver ions comprises the steps of reserving service water as for-electrolysis water in a vessel, electrolyzing the service water by means of silver electrodes immersed in the service water so as to generate silver ions in the service water, and spraying the service water containing the silver ions for the purpose of sterilization.
However, the above method has a problem that since the silver electrodes are eluted by the electrolysis, the electrodes become unable to be used as electrodes due to the elution of the electrodes even if polarities of the electrodes are switched, thereby decreasing a sterilizing effect. Further, the method also has a problem that since a relatively expensive noble metal is used in the electrodes, costs increase steeply when the electrodes are used over a long time period.
With this being the situation, as still another sterilization method, there is a method comprising the steps of producing electrolyzed water containing a high concentration of hypochlorous acid through electrolysis using electrodes and carrying out sterilization by use of the electrolyzed water. However, the method has the following problem. That is, when the electrolyzed water containing hypochlorous acid is used, salts remain where the solution has been applied, so that when the electrolyzed water is used for sterilizing hands and fingers, the hands and fingers must be rinsed after the sterilization.
The present invention has been conceived so as to solve the technical problems of the prior art. An object of the present invention is to propose an electrode for electrolysis which takes into consideration safety to human bodies and environmental pollution upon disposal of the electrode, produces ozone with high efficiency and has excellent durability, a production process of the electrode, and an electrolytic process for producing ozone or active oxygen.
Further, another object of the present invention is to provide an electrolyzed water producing device which can achieve sterilization by using electrolyzed water which exhibits a high sterilizing effect without using a chlorine-based agent.